BEIJING — Chinese leaders pushed back at visiting Vice President Joseph R. Biden Jr. on Wednesday over what they assert is their right to control a wide swath of airspace in the bitterly contested East China Sea. But the Chinese also indicated that they had not decided how aggressively to enforce their so-called air defense identification zone, which has ignited tensions with Japan.

Shuttling from one feuding neighbor to the other, Mr. Biden arrived here from Tokyo to urge China’s president, Xi Jinping, to show restraint in the zone, which Mr. Biden said the United States regarded as illegitimate and a provocation.

After five and a half hours of meetings, in which Mr. Biden laid out the American case against China’s action and Mr. Xi made a forceful counterargument, senior administration officials said: “President Xi took on board what the vice president said. It’s up to China, and we’ll see how things will unfold in the coming days and weeks.”

Mr. Xi’s response suggested that China and Japan may be able to manage a standoff that had threatened to escalate dangerously, with China scrambling fighter jets over islands that are claimed by both countries.

“I was very direct about our firm position and our expectations in my conversation with President Xi,” the vice president said in a speech to business people on Thursday morning. He urged China to refrain from “taking steps that will increase tension” and to communicate better with its neighbors.

Mr. Xi, who cultivated personal ties to Mr. Biden when he was China’s vice president, sounded a more upbeat note about the broader relationship, though he conceded “regional hot-spot issues keep cropping up.”

He welcomed a somber-looking Mr. Biden as “my old friend” and said nothing directly about the air defense identification zone.

As Mr. Biden was meeting with Mr. Xi, a senior White House official issued blunt criticism of China’s broader human rights record, saying that even Americans doing business here were not secure.

“The Chinese people are facing increasing restrictions on their freedoms of expression, assembly and association,” said the national security adviser, Susan E. Rice, speaking at a human rights meeting in Washington. “This is shortsighted.”

For Mr. Biden, China’s sudden action last month upended what was meant to be a tour of Asia with a wide-ranging agenda. Instead, he has had to walk a fine line: defending an ally and rebuking a potential adversary, while preventing a spat over the islands from mushrooming into a wider conflict.

A day earlier in Tokyo, Mr. Biden condemned China’s action as an effort to “unilaterally change the status quo” and said it had raised “the risk of accidents and miscalculation.” He promised to raise those objections with Mr. Xi in Beijing.

Photo

Vice President Joseph R. Biden Jr., center, during a meeting with President Xi Jinping of China on Wednesday in Beijing.Credit
Lintao Zhang/Getty Images

Mr. Biden stopped short of calling on China to rescind the zone, something it is highly unlikely to do, given the nationalist sentiments that have been animated by its standoff with Japan. The American military has ignored the zone, sending B-52 bombers last week to fly through it.

Shortly after Mr. Biden arrived, the Chinese Foreign Ministry said the new air defense identification zone was a fact of life that the world needed to accept. The spokesman at the ministry, Hong Lei, described it as a “zone of cooperation, and not confrontation.”

Since the zone was announced on Nov. 23, 55 airlines from 19 countries had provided China with flight information, he said. The Federal Aviation Administration has advised civilian aircraft to comply with China’s request. The F.A.A.’s guidance, which officials said was routine, unsettled Japanese officials, who had instructed their carriers not to identify themselves to the Chinese. But Mr. Biden’s strong words, combined with his appeal to China’s top leader, appear to have smoothed over that flap.

An error has occurred. Please try again later.

You are already subscribed to this email.

“The vice president seems to have put them back on track,” said Michael J. Green, an adviser on Asia in the George W. Bush administration. “Beijing may not like it, and he probably did not want his trip to be all about this, but he had to send a strong message of dissuasion.”

Mr. Xi’s sanguine words were calculated to send a different message, according to China experts. “A reason for Xi’s tone is a desire to make U.S. allies, especially Japan, uneasy about U.S. support by suggesting subliminally that the U.S.-China relationship is more important than other relationships, and the U.S. is keeping it sound despite China-Japan relations,” said Jeffrey A. Bader, a former China adviser to President Obama.

Mr. Xi, repeating a phrase he used at a meeting with Mr. Obama in Southern California in June, said China wanted to build a “new model of major-country relations,” based on respecting each other’s core interests, collaborating on global problems and devising ways to “appropriately handle sensitive issues and differences between us.”

Mr. Biden, while embracing that formulation, said the relationship between China and the United States needed candor and trust. He said Mr. Xi had been candid in their previous meetings, and Mr. Biden’s aides said their exchanges were similarly uninhibited on Wednesday.

Another major area of focus, American officials said, was North Korea, which has entered another period of uncertainty with reports that a powerful uncle of the country’s supreme leader, Kim Jong-un, had been purged from his positions. Officials declined to say whether China had intelligence on the ouster of the uncle, Jang Song-thaek.

But they said Mr. Xi displayed renewed interest in pursuing a dual-track strategy of economic pressure and diplomacy to curb North Korea’s nuclear ambitions, prompted in part by the negotiations that recently led to an interim nuclear deal with Iran.

“They talked at some length about what the Iran example means for North Korea,” said a senior official, who spoke on the condition of anonymity to discuss the contents of the meeting.

Before his meeting with Mr. Xi, Mr. Biden dropped in on the consular section of the American Embassy to promote its efforts to streamline the issuing of visas, particularly to students seeking to study in the United States. While there, he delivered a pitch to a line of people, many of them teenagers, waiting to submit applications.

“We’re constantly looking for bright, intelligent, innovative young people to come to America and stay in America,” Mr. Biden said. “I hope you learn that innovation can only occur where you can breathe free, challenge the government, challenge religious leaders.”

Mr. Biden’s audience applauded respectfully, though his words were less relevant to them, since the embassy only processes visas for temporary stays.

Jane Perlez contributed reporting.

A version of this article appears in print on December 5, 2013, on Page A4 of the New York edition with the headline: Biden Urges Restraint by China in Airspace Dispute. Order Reprints|Today's Paper|Subscribe